Project Summary/Abstract: The goal of this study is to determine the impact of CD55 and JAK/STAT pathway dysregulation in alveolar macrophages (AMs) on chronic beryllium disease (CBD) progression. CBD is an important organ-specific immune-mediated disease, characterized by granulomatous lung inflammation, fibrosis, and death, due to end-stage respiratory insufficiency. Thus, CBD remains an important public health concern. The precursor to this disease (beryllium sensitization; BeS) progresses to CBD at a rate of approximately 6-8% per year. Although the binding and presentation of Be via ?Glu69-containing HLA-DP molecules to pathogenic CD4+ T cells provides an explanation for the genetic linkage of DP2 to CBD and BeS, this does not explain the progression of BeS to CBD. Furthermore, DP2 is found in up to 40% of Be-workers without evidence of BeS or CBD. Thus, additional mechanisms must be involved in progression of BeS to CBD. Our hypothesis is that CBD AMs downregulate the negative immunoregulatory gene CD55 and its pathway and overexpress the positive regulatory activating JAK/STAT pathway, which augments the immune response to Be and progression from BeS to CBD. In Aim 1, we will define if CD55 on AMs is a negative regulator in the immune response to Be in AMs from BeS patients. Specifically, using either the overexpression of the CD55 genes using a adenovirus overexpression system and agonistic antibody or the reduction of CD55 genes using adenovirus knockdown system and neutralizing antibody of CD55, we will determine the impact of alteration of CD55 on consequential functional changes in TNF-? production, phenotype (CD16, CD40, CD80, CD86, HLA- DR), JAK/STAT activation and BeLPT comparing CBD, BeS and controls. Finally, using RNA-seq, we will investigate the regulatory networks associated with the downregulation of CD55 in CBD compared to BeS; In Aim 2, we will determine if the JAK/STAT pathway is a positive regulator of the immune response to Be in AMs and is increased in AMs from subjects with CBD compared to BeS. Specifically, AMs from CBD will be compared to those from BeS and controls subjects, assessing either the overexpression of the JAK/STAT pathway genes using a adenovirus overexpression system or the reduction of the JAK/STAT pathway genes using adenovirus knockdown system and pharmacological JAK1- 3 inhibitors on the Be immune response. We will evaluate the changes in TNF-? production, phenotype (CD16, CD40, CD80, CD86, HLA-DR), and BeLPT. Finally, using RNA-seq we will define the regulatory networks associated with the overactivation of the JAK/STAT pathway. In Aim 3, we will investigate whether the CD55 and JAK /STAT pathway are associated with CBD and progression from BeS to CBD, compared to BeS, using a longitudinal study and validate these findings in a larger longitudinal population to determine if these genes and pathways reveal potential novel biomarkers of diagnosis and prognosis for CBD. At the end of this project we will determine the key regulatory genes and pathways of exposure-mediated immune dysregulation in AMs that are associated with disease progression and reveal potential biomarkers for clinical prognosis and diagnosis. The results obtained from this study will improve our understanding of factors involved in the development of CBD, as well as targets for therapy, and will serve as a model of other exposure-related immune responses and environmentally-induced chronic diseases.